This invention relates to novel and useful agricultural formulations of herbicidal agents which exhibit poor solubility characteristics in both aqueous and organic media.
Emulsifiable suspension concentrate compositions (or oil flowable dispersions) are compositions which consist essentially of an active agent in a solid state suspended in a non-aqueous liquid containing a surfactant or a mixture of surfactants and said compositions having the property of forming an emulsion when diluted with water.
Emulsifiable suspension concentrate compositions containing pesticides such as herbicides and fungicides as the active agent and paraffinic oils as the non-aqueous liquid are described in European Patent Applications EP-A1-243872 and EP-A2-142670. However, said patent applications do not describe the use of aromatic solvents as the non-aqueous liquid.
Herbicidal agents, such as N-phosphonomethylglycine (glyphosate) and 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid (imazapyr), are especially useful for controlling undesirable plant species when applied postemergence. In addition to being highly effective herbicides, said compounds are zwitterionic in nature and generally relatively insoluble in both aqueous and non-aqueous media. Therefore, these types of herbicidal agents are routinely formulated as the corresponding salts as described in European Patent Application EP-A2-220902 and U.S. Pat. No. 4,816,060.
It is an object of this invention to provide an emulsifiable suspension concentrate composition of the free acids of a herbicidal agent, such as N-phosphonomethylglycine and 2-(imidazolin-2-yl)pyridine carboxylic acids, without the pre-formulation of the corresponding herbicidal salts. It is an object of this invention to produce herbicidal compositions which are physically stable and readily dilutable in hard or soft water to give a sprayable herbicidal emulsion.